Irradiation system including an electron-beam scanner

ABSTRACT

A property of a treatment beam is controlled during a scanning period. A portion of a region is exposed to an imaging x-ray beam during a scanning period, the imaging x-ray beam being generated by an electron-beam scanner. X-ray radiation from the region is detected, the x-ray radiation representing an attenuation of the imaging x-ray beam caused by the portion of the region. A first image of the portion of the region is generated based on the detected x-ray radiation. A characteristic of the portion of the region is determined from the generated first image. An input derived from the characteristic is generated, the input configured to cause a source of a treatment beam to modify a property of the treatment beam. The source of the treatment beam modifies a property of the treatment beam during the scanning period by providing the input to the source of the treatment beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/503,560 titled IRRADIATION SYSTEM INCLUDING AN ELECTRON-BEAM SCANNERand filed on Jul. 15, 2009, which claims the benefit of U.S. ProvisionalApplication Ser. No. 61/094,549 titled IRRADIATION SYSTEM INCLUDING ANELECTRON-BEAM SCANNER and filed on Sep. 5, 2008, and U.S. ProvisionalApplication Ser. No. 61/081,360, titled IRRADIATION WITH E-BEAM SCANNERand filed on Jul. 16, 2008, all of which are incorporated by referencein their entirety.

TECHNICAL FIELD

This disclosure relates to an irradiation system that includes anelectron-beam scanner.

BACKGROUND

Computer tomography (CT) systems can be used to image a patient,including, for example, a patient's tumor. An irradiation system candeliver high-energy radiation, such as x-ray radiation, to the tumor todestroy the tumor.

SUMMARY

In one general aspect, a system includes an electron-beam scanner, asource of irradiation energy, and a processor. The electron-beam scannerincludes an electron emitter configured to produce an electron beam, anelectron accelerator configured to accelerate the electron beam toward atarget that produces an x-ray beam in response to being struck by theelectron beam, a steering device configured to scan the electron beamalong the target such that the produced x-ray beam is positionedrelative to a portion of a region to be imaged, and a detectorconfigured to sense x-ray radiation from the region and produce arepresentation of the sensed radiation. The source of irradiation energyis configured to produce a treatment beam. The electron beam scanner andthe source of irradiation energy are positioned to allow the portion ofthe region to be exposed to the treatment beam and the produced x-raybeam concurrently. The system also includes a processor operable toreceive the representation of the sensed x-ray radiation, determine acharacteristic of the imaged portion of the region based on therepresentation of the sensed x-ray radiation, and modify a property ofthe treatment beam based on the characteristic.

Implementations may include one or more of the following features. Theelectron beam scanner may be positioned at an angle relative to adirection of propagation of the treatment beam. The system also mayinclude a gantry, and the electron beam scanner and the source ofirradiation energy may both be located within the gantry. Theelectron-beam scanner may be movable with respect to the gantry and theprocessor may be further operable to determine a position of theelectron-beam scanner relative to the gantry and a position of theproduced x-ray beam relative to the gantry.

In some implementations, the characteristic of the portion of the regionmay include one or more of a position of the portion, a size of theportion, and a shape of the portion. The processor may be furtheroperable to generate an image of the region based on the representationof the sensed radiation. The portion may include a biological structurewithin a human patient. The region may include a pancreas, and theportion of the region may include a portion of the pancreas.

To control the treatment beam based on the characteristic, the processormay be further operable to provide an input to the source of irradiationenergy, the input being derived from the characteristic of the portionof the region and the input being sufficient to cause the source ofirradiation energy to modify a property of the treatment beam. Theprocessor may provide the input to the source of irradiation energywhile the produced x-ray beam illuminates the portion of the region. Theprocessor may provide the input to the source of irradiation energywhile the portion of the region is imaged by the x-ray beam. Theprocessor may provide input to the source of irradiation energy during atreatment session. The property of the treatment beam may include one ormore of a beam profile of the treatment beam and an intensity of thetreatment beam. The characteristic of the object may include a size andshape of the object, and the input to the source of irradiation energymay be sufficient to cause the source of irradiation energy to modify abeam profile of the treatment beam such that the profile approximatelymatches a size and shape of the object.

In another general aspect, during a scanning period in which a portionof a region is imaged by an electron-beam scanner, first data producedby the electron-beam scanner is received. The first data includes afirst indication of a characteristic of the portion. During the scanningperiod, a characteristic of the portion from the first data isdetermined. During the scanning period, a first input derived from thecharacteristic is provided to a source of a treatment beam, the firstinput being sufficient to cause the source of the treatment beam tomodify a property of the treatment beam. During the scanning period,second data produced by the electron-beam scanner is received. Thesecond data is received after the first data and the second dataincludes a second indication of the characteristic of the portion.During the scanning period, the characteristic of the portion from thesecond data is determined. During the scanning period, a second inputderived from the characteristic determined from the second data isprovided to the source of an irradiation beam, the second input beingsufficient to cause the source of the treatment beam to modify theproperty of the treatment beam to account for the characteristicdetermined from the second data.

Implementations may include one or more of the following features. Theproperty of the treatment beam may include a beam profile of thetreatment beam. The characteristic of the portion may include a shape ofthe portion, and the shape of the portion may vary during the scanningperiod. The portion may move during the scanning period. The region mayinclude a human patient and the portion of the region may include abiological structure within the human patient. The property of thetreatment beam may be a beam profile of the treatment beam and the firstinput and the second input are inputs sufficient to cause a leaf of amulti-leaf collimator coupled to the source of the treatment beam tomove such that the beam profile is modified. The characteristic of theportion of the region may be a position, and the first input and thesecond input are inputs sufficient to cause the source of the treatmentbeam to direct the treatment beam toward the position of the portion.The portion of the region may include a biological structure of apatient, and the scanning period may be a continuous treatment sessionduring which the patient remains in the region and the treatment beamirradiates the biological structure.

In some implementations, the second input may be provided to the sourceof the irradiation beam no more than one hundred milliseconds after thefirst input is provided to the source of the irradiation beam.

In another general aspect, a treatment beam is controlled during ascanning period. A portion of a region is exposed to an imaging x-raybeam during a scanning period, the imaging x-ray beam being generated byan electron-beam scanner. X-ray radiation from the region is detected,the x-ray radiation representing an attenuation of the imaging x-raybeam caused by the portion of the region. A first image of the portionof the region is generated based on the detected x-ray radiation. Acharacteristic of the portion of the region is determined from thegenerated first image. An input derived from the characteristic isgenerated, the input configured to cause a source of a treatment beam tomodify a property of the treatment beam. The source of the treatmentbeam modifies a property of the treatment beam during the scanningperiod by providing the input to the source of the treatment beam.

Implementations may include one or more of the following features. Thecharacteristic of the portion may include the position of the portion,and causing the source of the treatment beam to modify a property of thetreatment beam may include modifying a direction of propagation of thetreatment beam such that the treatment beam irradiates the portion.

In another general aspect, an apparatus to control a treatment beambased on data from an electron-beam scanner is assembled. A source of anirradiation energy configured to produce a treatment beam is positionedin a housing, and an electron-beam scanner configured to produce anx-ray imaging beam is positioned in the housing relative to the sourceof irradiation energy. The positioning of the electron-beam scannerallows an object in a region within the housing to be exposed to thetreatment beam and the x-ray imaging beam concurrently.

Implementations of the techniques discussed above may include a methodor process, a system or apparatus, or computer software on acomputer-readable medium.

DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate perspective views of a circular configurationelectron-beam scanner.

FIG. 1C illustrates an example of a collimator.

FIG. 1D illustrates an example of a detector system.

FIGS. 1E and 1F illustrate example geometries for an electron-beamscanner.

FIG. 2 illustrates an example of a linear configuration electron-beamscanner.

FIG. 3 illustrates a horizontal cross-section of an irradiation systemthat includes an electron-beam scanner.

FIG. 4A illustrates a side vertical cross-section of a system thatincludes an irradiation system and an electron-beam scanner.

FIGS. 4B and 4D illustrate front perspective views of the system shownin FIG. 4A.

FIG. 4C illustrates a rear perspective view of the system shown in FIG.4A.

FIGS. 5A and 5B illustrate rear perspective views of another system thatincludes an irradiation system and an electron-beam scanner.

FIG. 5C illustrates a front perspective view of the system shown inFIGS. 5A and 5B.

FIG. 5D illustrates a front vertical cross-sectional view of the systemshown in FIGS. 5A and 5B.

FIG. 5E illustrates a side vertical cross-sectional view of the systemshown in FIGS. 5A and 5B.

FIG. 5F illustrates a bottom cross-sectional view of the system shown inFIGS. 5A and 5B.

FIG. 6 is a block diagram of an example system that includes anirradiation system and an electron-beam scanner.

FIG. 7 is an example process for modifying a property of a treatmentbeam based on a characteristic of an object imaged by an electron-beamscanner.

Like reference numbers refer to like elements.

DETAILED DESCRIPTION

An electron-beam scanner capable of rapidly imaging a region of apatient (such as a tumor) can be combined with an irradiation systemthat delivers high-energy radiation (which may be referred to as atreatment beam) to the tumor imaged by the electron-beam scanner. Theelectron-beam scanner (e-beam scanner) scans a region at a rate of tenscans per second or higher and, thus, is able to generate clear imagesof the region even if the region (or a portion of the region) moves. Theimages generated by the electron-beam scanner are used to control andshape the treatment beam such that the treatment beam matches the imagedregion or portion thereof, for example a tumor within or on the imagedregion of the patient. In this manner, the amount of radiation deliveredto the tumor may be increased relative to the amount of radiationdelivered to the surrounding tissue. For convenience, area within or ona patient (such as, for example, a tumor, an organ, a portion of anorgan, or another type of biological structure) that is to receivetreatment may be referred to as an object.

Referring to FIGS. 1A and 1B, an example electron-beam scanner 100 scansa region 105 with an electron beam generated from a first electronemitter 110 and a second electron emitter 115. The first and secondelectron emitters may be electron guns that emit a beam of electrons. Insome implementations, the first and second electron emitters may bethermionic emitters, electron emitters made from carbon nanotubes, orphoto emitters. The first and second electron emitters may both be thesame type of emitter, or the first and second electron emitters may eachbe a different type of emitter. FIG. 1A shows a rear perspective view ofthe electron-beam scanner 100 and FIG. 1B shows a front perspective viewof the electron-scanner 100. The electron-beam scanner 100 is a circularconfiguration of an electron-beam scanner. Other implementations mayinclude different configurations, such as a linear configuration of theelectron beam scanner. For example, FIG. 2 shows a linear configurationof an electron-beam scanner.

The electron beam from the electron guns 110 and 115 creates a scan beam(not shown) within the region 105. The scan beam scans the region 105 ata rate of ten scans per second or higher (for example, about fifty scansper second) to image objects within the region 105 (such as a portion ofa human patient, a biological structure, or a tumor within the patient).The object may be considered to be a portion of the region 105. Becausethe region 105 is scanned at a rate of at least ten scans per second,tumors within the patient that move as a result of normal bodilyfunctions (even when a person is lying still or attempting not to move),such as a tumor in or around the patient's lungs that moves continuouslyas the patient breathes, may be imaged as the tumors move. Scanning theregion 105 at a rate of at least ten scans per second allows clear,non-blurred images of the moving tumors to be generated. Thus, theimages generated by scanning the region 105 may be used to determine aprofile or shape of a tumor within the patient as the tumor moves due tonormal bodily functions.

The electron-beam scanner 100 is combined with an irradiation system(not shown) that delivers a high-energy radiation treatment beam (suchas gamma radiation or x-ray radiation) to the tumors in order to destroythe tumor. By combining the electron-beam scanner 100 with theirradiation system, the images generated from the electron-beam scanner100 may be used to control a property of the treatment beam, such as thedirection and/or beam shape of the treatment beam, provided by theirradiation system. In particular, the determined profile of the tumoris used to digitally control a beam profile and position of thetreatment beam from the irradiation system. Digitally controlling thebeam profile and position of the treatment beam allows the treatmentbeam to be matched to the tumor such that the tumor receives as muchradiation as possible (thus helping to ensure that the tumor isdestroyed) while also preventing or minimizing the exposure of nearbytissues and structures to the treatment beam (thus helping to preventdamage to the nearby tissue and structures). Additionally, because theelectron-beam scanning system 100 scans the region 105 at a rate of atleast ten scans per second, the treatment beam can be quickly adjustedto track and target the changing shape and/or location of the tumor (forexample, as the tumor moves due to normal bodily functions).

In the example shown in FIG. 1A, the electron-beam scanner 100 includestwo electron guns, the electron gun 110 and the electron gun 115. Eachof the electron guns 110 and 115 include a high-voltage connector thatconnects the electron gun 110 and the electron gun 115 to a powersource. In the example shown, the electron gun 110 includes thehigh-voltage connector 111, and the electron gun 115 includes thehigh-voltage connector 116. The power source supplies a voltagesufficient to generate a voltage potential through which electrons inthe electron beam are accelerated by accelerators 112 and 117 to atarget (not shown), to produce x-ray radiation. The accelerators 112 and117 may be referred to as electron accelerators. The produced x-rayradiation passes through a collimator 125, which shapes the x-rayradiation into a scan beam that can fill the region 105. Referring toFIG. 1C, the collimator 125 may be a rounded shell of a high-densitymaterial, such as lead or tungsten, that blocks x-rays. The collimator125 includes an open slot 127 through which the x-rays generated fromthe electron beam striking the target pass to form an x-ray scan beamthat fills the region 105. In some implementations, the scan beam may bea cone beam of x-ray radiation and the electron-beam scanner 100 may bea cone beam volumetric tomography system.

Referring again to FIGS. 1A and 1B, the object to be imaged may extendbeyond the scan region 105. However, the scan region 105 may be appliedto the portions of the object that are outside of the scan region 105 bymoving the scan region 105 or by moving the object to be imaged into orthrough the scan region 105. Radiation from the scan beam that passesthrough the scan region 105 and through items within the scan region 105is detected by a detection system 130 and used to generate an image ofthe scan region 105. The images may be three-dimensional computedtomography images.

Referring to FIG. 1D, an example of the detection system 130 is shown.The detection system 130 includes a material 134 that is sensitive tothe energies in the scan beam. The material 134 may be a scintillationmaterial that is sensitive to the energies in the scan beam and convertsthe energies in the scan beam into light. The material 134 may be acrystalline material such as cadmium tungsten (CdW), and the material134 may have an overall circular or semi-circular cross-section to matchthe circular cross section of the region 105. However, the material 134is made up of rectangular sections, or stripes. Multiple stripes make upan arc, but the individual stripes are rectangular or otherwise linear.The detector 134 may be mounted on an arc around the region 105. Forexample, the material 134 may be formed as a 180-degree half-circlecentered around the region 105. In other examples, the detector 134 maybe formed as an arc of more than 180-degrees, such as a 210-degree arcaround the region 105. The detection system 130 also includes detectorboard electronics 136. The detector board electronics 136 converts theradiation sensed by the material 134 into an electrical signal fromwhich an image of the region 105 is made.

Referring again to FIGS. 1A and 1B, although the example shown in FIG.1A includes the two electron guns 110 and 115 and the two correspondingaccelerators 112 and 117, in other examples more or fewer electron gunsmay be used. Using more than one electron gun allows for the size of thesystem 100 to be reduced as compared to implementations in which oneelectron gun is used. For example, each electron gun may be able to scanover a distance that is determined by the distance of the electron gunfrom the object to be imaged and the maximum electron beam deflectionangle. Thus, implementations that include one electron gun scan thex-ray beam over a relatively shorter total distance or include electronguns that are placed further from the object to be imaged in order to beable to scan the x-ray beam over a longer total distance. However, byusing more than one electron gun, the electron guns may be placed closerto the object to be imaged because, together, the electron guns scan thex-ray beam over a longer distance than possible with a single electrongun scanning at the maximum deflection angle. Thus, using two electronguns results in the electron-beam scanner 100 being about half of thesize of a system that uses one electron gun.

Referring to FIG. 1E, an example geometry of a system that uses twoelectron guns (such as the electron-beam scanner 100) is shown, and,referring to FIG. 1F, an example geometry of a system that uses oneelectron gun is shown. In each of the example geometries, the electronguns produce a beam having a total deflection angle of 70.2 degrees andthe beam is scanned over a total distance of one meter at a targetlocation “T.” However, using the geometry shown in FIG. 1E results in asmaller system because the two electron guns are placed 0.34 meters fromthe target location “T” as compared to the one electron gun in thegeometry shown in FIG. 1F, which is placed 0.71 meters from the targetlocation “T.” Thus, using the two electron guns 110 and 115 shown inFIG. 1A results in a smaller system to scan the same size region.

Referring to FIG. 2, an example of a linear configuration electron-beamscanner 200 is shown. The electron-beam scanner 200 scans a region 205with a scan beam (not shown) that is generated from a first electron gun210 and a second electron gun 215. The scan beam scans the region 205 ata rate of ten scans per second or higher (e.g., fifty scans per second)to image objects within the region 205 (such as a portion of a patient225, a biological structure, or a tumor within the patient 225). Thescan beam is a beam of radiation such as an x-ray beam. For example, thescan beam may be a cone beam of radiation and the electron-beam scanner200 may be a cone beam volumetric tomography system.

Images generated by scanning the region 205 may be used to determine aprofile of the tumor within the patient 225, even as the tumor moves,and the determined profile is used to digitally control a beam profileand position of an x-ray treatment beam used to irradiate and destroythe tumor. Objects outside of the region 205 may be imaged by the scanbeam by moving the objects into the region 205 and/or by moving theregion 205.

In the example shown in FIG. 2, a portion of the patient 225 is withinthe region 205, and the scan beam is used to image the portion of thepatient 225 along with biological structures and/or other objects withinthe portion of the patient 225. Radiation from the scan beam that passesthrough the patient 225 is detected by a detection system 230 and usedto generate an image of the region 205. The images may bethree-dimensional computed tomography images. The detector system 230includes a detector array that is sensitive to the energies included inthe scan beam and electronics that convert the sensed energies intoelectrical signals that are used to generate an image of the region 205.

Because the region 205 is scanned at a rate of at least ten scans persecond, structures within the patient 225 that move as a result ofnormal bodily functions, such a tumor in or around the patient's 225lungs that moves continuously as the patient 225 breathes, may be imagedas the structures move. Scanning the region 205 at a rate of at leastten scans per second allows clear, non-blurred images of the movingstructures to be generated.

The electron-beam scanner 200 includes two electron guns, the electrongun 210 and the electron gun 215. Each of the electron guns 210 and 215respectively include the high-voltage connectors 211 and 216, whichconnect the electron gun 210 and the electron gun 215 to a power source.The power source supplies a voltage sufficient to generate a voltagepotential through which electrons in the electron beam are beaccelerated by accelerators 212 and 217 to a target (not shown), toproduce x-ray radiation.

Although the example shown in FIG. 2 includes the two electron guns 210and 215 and the two corresponding accelerators 212 and 217, in otherexamples more or fewer electron guns may be used. As discussed abovewith respect to FIGS. 1E and 1F, using more than one electron gun allowsfor the size of the system 200 to be reduced as compared toimplementations in which one electron gun is used.

Referring to FIG. 3, a horizontal cross-section of an irradiation system300 that includes an electron-beam scanner 305 is shown. The irradiationsystem 300 also includes a gantry 310 and a patient table 320. In theexample shown, the electron-beam scanner 305 is similar to the linearconfiguration electron-beam scanner 200 discussed with respect to FIG.2. However, in other implementations, the electron-beam scanner 305 maybe a circular configuration electron-beam scanner such as theelectron-beam scanner 100 discussed with respect to FIGS. 1A and 1B. Theelectron-beam scanner 305 is placed in the gantry 310. The electron-beamscanner 305 is used to image a portion of the patient to, for example,image a tumor within the patient. The irradiation system 300 produces atreatment beam that is shaped and directed toward the tumor within thepatient to destroy the tumor by irradiating the tumor with the treatmentbeam. Placing the electron-beam scanner 305 in the gantry 310 allows thetreatment beam be moved with respect to the patient table 320 such thatthe treatment beam can be directed to the portion of the patient thatincludes the tumor to be destroyed. Additionally, placing theelectron-beam scanner 305 in the gantry allows the scan beam to be movedand the position of the scan beam tracked with respect to the knownposition of the gantry 310.

Referring to FIGS. 4A and 4B, a side vertical cross-sectional view of anexample system 400 and a front perspective view of the system 400 arerespectively shown. The system 400 includes an irradiation system 405that produces a high-energy treatment beam 460 and an electron-beamscanner system that is used to image a patient 457. In the example shownin FIGS. 4A and 4B, the electron-beam scanner system is a linearconfiguration electron-beam scanner system similar to the electron-beamscanner system discussed above with respect to FIG. 2. The system 400includes a gantry 410, which houses an electron-beam scan chamber 420that produces a scan beam 440 within an x-ray beam region 445. In someimplementations, the electron-beam scan chamber 420 may be removed fromthe gantry 410, perhaps by a robotic arm. In other implementations, theelectron-beam scan chamber 420 may be permanently, or semi-permanently,affixed to the gantry 410 by, for example, bolting the electron-beamscan chamber 420 to the gantry 410.

In the example shown in FIG. 4A, images of the patient 457, andbiological structures within or on the patient 457, are generated usingthe electron-beam scanner system. The images of the patient 457 may bevolumetric computed tomography images. A high-energy x-ray beam 460,which may be referred to as a treatment beam 460, is produced by theirradiation system 405 and irradiates a target structure, such as acancerous tumor, within the patient 457. The target structure isidentified from images of the patient 457 generated by the electron-beamscanner system.

The treatment beam 460 delivers x-ray radiation to the tumor, or othertarget structure, while minimizing or eliminating the exposure of nearbytissue and structures to the radiation in the treatment beam 460. Tominimize or eliminate the exposure of nearby tissue to the radiation inthe treatment beam 460, the treatment beam 460 is shaped by a digitallycontrolled multi-leaf collimator and delivered to the site of the targetstructure as identified by the images of the tumor in the patient 457that are generated by the electron-beam scanner system. The multi-leafcollimator may be made up of multiple segments of a material, such aslead or tungsten, that blocks energies included in the treatment beam460. The segments of the collimator move independently, and bycontrolling the placement of the segments, selective portions of thetreatment beam 460 may be blocked, thus controlling the shape of thebeam profile of the treatment beam 460. For example, the multi-leafcollimator may include sixty-four individually controllable and moveablesegments that may be moved in and out of the path of the treatment beam460 in order to selectively block and transmit portions of the treatmentbeam 460. In other examples, the multi-leaf collimator may include moreor fewer individually controllable and moveable segments.

Images of a target structure within the patient 457 are generated by theelectron-beam scanner system and analyzed to determine the shape (orprofile) of the target structure and the location of the targetstructure within the patient 457. In particular, images of the targetstructure are generated and analyzed at a rate of at least ten imagesper second. This allows the profile of the target structure and thelocation of the target structure to be tracked even if the targetstructure moves while the region 445 is scanned.

Additionally, the electron-beam scanner 420 may be angled at an angle465 with respect to the treatment x-ray 460 such that detectors (such asthe detectors 230) do not block the treatment beam 460 and prevent thetreatment beam 460 from reaching the patient 457. The angle 465 may bedefined with respect to a direction of propagation of the treatment beam460. The scan beam 440 may be angled with respect to the treatment beam460 by installing the electron-scanner system in the gantry 410 at theangle 465. The angle 465 may be, for example, thirty-five degrees orless, or the angle 465 may be between three and seventy-five degrees.Positioning the scan beam 440 at the angle 465 prevents the detectorsfrom blocking the treatment beam 460. Alternatively, or additionally,the detectors may be displaced or offset laterally along the gantry 410with respect to the treatment beam 460 such that the detectors do notblock the treatment beam 460 but the detectors are still positionedclose enough to the scan beam 440 to ensure that the detectors sensesufficient signal to form an image of the region 445. For example, thedetectors may be displaced 100 millimeters closer to a head of thepatient 457 or closer to the feet of the patient 457 with respect to thetreatment beam 460.

Referring to FIG. 4C, a rear perspective view of the system 400 isshown. In the example shown in FIG. 4C, the electron-beam scan chamber420, detectors, and the treatment beam 460 are moved with respect to thepatient 357 within the gantry 410 to image and irradiate differentportions of the patient 457. Because the electron-beam scanner 420 andthe treatment beam 460 are moved together within the gantry 410 withrespect to the patient 457, the images of the region 445 remainregistered with respect to the gantry 410 such that the location of thestructure to be irradiated with the treatment beam 460 is known and canbe targeted by the treatment beam 460. Referring to FIG. 4D, a frontview of the system 400 is shown. In the example of FIG. 4D, the electronbeam scan chamber 420, the x-ray beam region 445, and the treatment beam460 have moved counter clockwise by about forty-five degrees as comparedto the example shown in FIG. 4B.

Referring to FIG. 5A, a vertical perspective rear view of an examplesystem 500 that combines a circular configuration electron-beam scannersystem and an irradiation system is shown. The electron-beam scannersystem in the system 500 has a circular configuration that may besimilar to the electron-beam scanner system 100 discussed above withrespect to FIGS. 1A and 1B. The scan beam produced by the electron-beamscanner system included in the system 500 scans an object within a scanregion 525. In the example shown, the electron-beam scanner system has acircular configuration and the region 525 has a circular, orsemi-circular, cross-section.

The system 500 is placed within a gantry 510, and electron guns 515 and520 generate an electron beam that is used to generate a scan beam thatscans a portion of a patient 522 that is within the scan region 525while the patient 522 rests on a table 523. Radiation from the scan beamthat passes through the patient 522 is detected by a detector 530 (whichmay be a circular detector similar to the detector 130 discussed withrespect to FIGS. 1A and 1D) to form an image of the portion of thepatient 522 that is within the scan region 525 and biological structureswithin and/or on the patient 522. Thus, the electron-beam scanner systemis used to generate images of the portion of the patient 522 that iswithin the region 525. Profiles of a target structure within or on thepatient 522 (such as a tumor) are determined from the images, and theprofiles are used to control a therapy beam 535, which is generated bythe irradiation system. The therapy beam 535 may be referred to as atreatment beam 535. In particular, the profiles may be used to controlthe beam profile of the therapy beam 535 and direction of the therapybeam 535 such that the irradiation of the target structure is maximizedwhile radiation to the tissue and biological structures in the vicinityof the target structure is minimized. In the example shown, thetreatment beam 535 is offset from the detector 530 such that thedetector 530 does not prevent the treatment beam 535 from reaching thepatient 522.

FIGS. 5B-5F show various views of the system 500. In particular, FIG. 5Bshows a rear perspective view of the irradiation system 500, FIG. 5Cshows a front perspective view of the irradiation system 500, FIG. 5Dshows a front vertical cross-sectional view of the irradiation system500, FIG. 5E shows a side vertical cross-sectional view of theirradiation system 500, and FIG. 5F shows a bottom cross-sectional viewof the irradiation system 500.

FIG. 6 is a block diagram of an example system that includes anirradiation system 620 and an electron-beam scanner 610. The irradiationsystem 600 includes an irradiation source 620 that produces a treatmentbeam 622. The system 600 includes an e-beam scanner 610, a source ofirradiation energy 620, an input/output interface (I/O interface) 630, aprocessor 640, and an electronic storage 650. The e-beam scanner may beany of the e-beam scanners discussed above. In some implementations, thee-beam scanner 610 may be an e-beam scanner similar to those discussedin U.S. Pat. No. 7,428,297, which is hereby incorporated by reference inits entirety.

The e-beam scanner 610 produces an x-ray beam that is used to image aregion that is also irradiated by the treatment beam produced by thesource of irradiation energy 620. The e-beam scanner includes anelectron emitter 612 that emits a beam of electrons, an electronaccelerator 614 that accelerates the electrons in the beam of electrons,and a target material 615 that produces x-rays in response to beingstruck by the accelerated electrons.

The e-beam scanner 610 also includes a steering device 616, which movesthe beam of electrons across the target material 615. Moving the beam ofelectrons across the target material 615 may also be considered scanningthe beam of electrons across the target material 615 or positioning thebeam of electrons at a particular place along the target material 615.Moving the beam of electrons across the target material 615 results inthe x-ray beam produced by the interaction with the target material 615having a corresponding motion relative to the portion of the region. Asa result, the produced x-ray beam moves across the region to image theregion or the portion of the region. The steering device 616 may includea magnet that is positionable to direct the beam of electrons in aparticular direction.

Thus, in contrast to systems that use a conventional computed tomography(CT) scanner in which the source of the imaging beam itself moves, thex-ray beam produced by the e-beam scanner 610 moves through the regiondue to the action of the steering device 616 on the electron beam.Because the source of x-rays is not required to move (rather the x-raybeam itself is steered as a result of the electron beam being steered bythe steering device 616), the e-beam scanner 610 is able to scan theregion much more quickly than is possible with a conventional CT scannersystem. For example, the weight of a typical CT scanner generallyprevents a CT scanner from taking more than about two measurements ofthe imaged region per second. In contrast, the e-beam scanner 610 maytake measurements fifty to one hundred times per second. Additionally,the size of the e-beam scanner 610 allows it to fit into a gantry withthe source of irradiation energy to allow for concurrent imaging andtreatment. Finally, the positioning of the e-beam scanner 610 and thesource of irradiation energy at, for example, an angle with respect toeach other or tilted with respect to each other, allows the portion ofthe region to be imaged with the x-ray beam produced by the e-beamscanner 610 while also being irradiated with the treatment beam 622 fromthe source of irradiation energy.

The e-beam scanner 610 also includes a detector 618 that senses x-rayradiation that passes through an imaged portion of a region. The imagedportion may be a portion of a human or non-human patient. For example,the imaged portion may be a suspected or known tumor within a regionthat includes the patient's pancreas. The detector 618 produces arepresentation of the sensed x-ray radiation. As compared to the x-rayradiation produced by the interaction of the electron-beam and thetarget material 615, the sensed x-ray radiation has an intensity that isattenuated as a result of passing through items the portion of theregion. Thus, the representation of the sensed x-ray radiationrepresents the amount of attenuation caused by the portion of theregion.

In implementations in which the detector 618 is a scintillator, thedetector 618 produces visible light having an intensity proportional tothe amount of detected x-ray radiation. The e-beam scanner 610 alsoincludes detector electronics 619 that transform the representation ofx-ray energy into a form that may be processed by the processor 640. Forexample, the detector electronics 619 may include a visible light sensorcoupled to an analog-to-digital converter that produces a digital valuethat represents the amount of x-ray energy sensed by the detector 618.

The source of irradiation energy 620 provides a treatment beam 622 to aregion that is imaged by the e-beam scanner 610. The system 600 includesboth the e-beam scanner 610 and the source of irradiation energy 620,and the e-beam scanner 610 and the source of irradiation energy 620 arearranged such that the region may be imaged by the x-ray imaging beamfrom the e-beam scanner 610 and irradiated with the treatment beam 622concurrently. For example, the e-beam scanner 610 may be tilted suchthat the treatment beam 622 and the x-ray imaging beam are at an anglewith respect to each other.

The system 600 also includes the source of irradiation energy 620. Thesource of irradiation energy 620 produces a treatment beam 622. Thesource 620 also includes a beam controller 624. The beam controller 624controls a property of the treatment beam 622. The property of thetreatment beam 622 may be a profile of the treatment beam 622, anintensity of the treatment beam 622, a location of the treatment beam622 relative to a housing of the source of irradiation energy 620,and/or a direction of propagation of the treatment beam 622. The profileof the treatment beam 622 may be a spatial distribution of energy in aplane that is perpendicular to the direction of propagation of thetreatment beam 622. For example, the beam controller 624 may be amulti-leaf collimator having movable leaves that block certain portionsof the treatment beam in order to shape the beam profile of thetreatment beam 622. The beam controller 624 also may cause the positionand/or the direction of propagation of the treatment beam 622 to change.The beam controller 624 also may control the intensity (or flux) of thetreatment beam 622.

The system 600 also includes an I/O interface 630, a processor 640, andan electronic storage 650. The electronic storage 650 storesinstructions, perhaps as a computer program, that, when executed, causethe processor to communicate with other components in the system 600.For example, the electronic storage 650 may store instructions thatcause the beam controller 624 to move the treatment beam 622. Theprocessor 640 executes instructions that cause the beam controller 624to modify or otherwise adjust a property of the treatment beam based oninformation received from the detector 618. In another example, theelectronic storage 650 stores instructions that, when executed, causethe processor 640 to generate images of the portion of the region basedon the representation of sensed x-ray radiation sensed by the detector618. The processor 640 also process commands received from the I/Ointerface 630. The I/O interface 630 may be any device or program thatallows a user to interact with the system 600. For example, the I/Odevice 630 may be a mouse, a keyboard, a display, or a touch screen.

FIG. 7 is an example process 700 for modifying a property of a treatmentbeam based on a characteristic of an object imaged by an electron-beamscanner. The process 700 may be performed on a processor such as theprocessor 640 discussed with respect to FIG. 6.

Data produced by an electron-beam scanner is received (710). The datamay be referred to as “first data.” The first data is received during ascanning period in which a portion of a region is imaged by the electronbeam scanner 610. The first data includes an indication of acharacteristic of the portion of the region. The first data may be animage, a series of images, and/or a video produced from the data sensedby the detector 618.

The region may be a portion of a patient's body, such as a pancreas,that moves continuously due to normal bodily functions, and the portionof the region may be a portion of the pancreas. As discussed above, theimaging x-ray beam produced by the electron-beam scanner 610 rapidlyscans the region, which allows moving organs and other moving structuresto be imaged.

The indication of the characteristic of the portion of the region may bedata values that allow an analysis tool, such as an edge detector orother signal processing technique, to process the data to determine thecharacteristic.

The scanning period may be a time during which a patient is imaged withthe x-ray imaging beam and concurrently treated with the treatment beam622. The scanning period may be considered to be a treatment sessionduring which a patient is treated with the treatment beam 622 to, forexample, irradiate a tumor within the patient. The treatment session maybe a continuous treatment session during which the patient remains inthe region. The scanning period may be contrasted with techniques inwhich images of a portion of the region are generated and analyzedduring an imaging session and then used at a later time, separate fromthe imaging session, to plan a treatment that uses the treatment beam622.

A characteristic of the portion of the region is determined from thefirst data (620). The characteristic is determined during the scanningsession. The characteristic may be a spatial characteristic, such assize, shape, an outline or partial outline, a profile, or an approximateshape that is the best match between the imaged object and a library ofpre-defined shapes. For example, the characteristic may be a location,shape, and/or size of a suspected tumor within a pancreas of a patient.In another example, the shape of the tumor in a particular direction maybe the characteristic. The particular direction may be a two-dimensionalprojection of the tumor and the organ that the tumor is within, on, ornear in the direction of propagation of the treatment beam 622.

An input derived from the characteristic is provided to the irradiationsource 620 (730). The input may be referred to as a “first input.” Thefirst input is sufficient to cause the irradiation source 620 to modifya property of the treatment beam 622. The property of the treatment beam622 may be one or more of a direction of propagation of the treatmentbeam 622, a beam profile of the treatment beam 622, an intensity of thetreatment beam 622, a timing of the treatment beam 622, and a positionof the treatment beam 622. The first input may cause the source 620 tomodify the treatment beam 622 by causing the beam controller 624 to moverelative to the treatment beam 622. The first input is derived from thecharacteristic such that the input causes the treatment beam 622 to bemodified to match the characteristic. For example, the characteristicmay be a shape of a suspected tumor, and the treatment beam 622 may bemodified to have a profile that matches the shape of the object. Inanother example, the treatment beam 622 may be modified by moving thetreatment beam to follow, or track, the position of a moving tumor. Suchmodifications may increase the amount of irradiation energy that reachesthe suspected tumor while decreasing the amount of radiation reachingthe surrounding healthy tissue.

Data produced by the electron-beam scanner is received during thescanning period (740). This data may be referred to as second data. Thesecond data is received after the first data, and the second dataincludes a second indication of the characteristic of the portion. Thesecond data is received during the scanning period but after the firstdata is received. The time between receipt of the first data and thesecond data is determined by the scan speed of the electron-beamscanner. For example, if the electron-beam scanner receives data fiftytimes per second, the second data may be received approximately 20milliseconds after the first data is received.

The characteristic of the portion is determined from the second dataduring the scanning period (750). For example, in implementations inwhich the position of the portion is the characteristic, the position isdetermined at the first time associated with the first data and thesecond time associated with the second data. Thus, the imaged portionmay be tracked over time.

An input derived from the characteristic determined from the second datais provided to the source 620 (760). This input may be referred to as asecond input. The second input is sufficient to cause the source 620 tomodify the property of the treatment beam 622 to account for thecharacteristic determined from the second data, and the second input isprovided during the scanning session. For example, the characteristicmay be a position of a tumor in a patient's pancreas, and the secondinput may be an input sufficient to cause the treatment beam 622 to moveto follow the tumor as it moves with the pancreas. Because of thefeatures of the electron-beam scanner 610, the treatment beam 622 ismodified during the scanning session. Thus, the treatment of the patientwith the irradiation beam is planned in real-time, or near-real time,while the patient is imaged. In some implementations, the first andsecond input are formatted such that the inputs are compatible withinputs that are produced by a standard CT scanner.

The techniques can be implemented in digital electronic circuitry, or incomputer hardware, firmware, software, or in combinations of them. Thetechniques can be implemented as a computer program product, i.e., acomputer program tangibly embodied in an information carrier, e.g., in amachine-readable storage device, in machine-readable storage medium, ina computer-readable storage device or, in computer-readable storagemedium for execution by, or to control the operation of, data processingapparatus, for example, a programmable processor, a computer, ormultiple computers. A computer program can be written in any form ofprogramming language, including compiled or interpreted languages, andit can be deployed in any form, including as a stand-alone program or asa module, component, subroutine, or other unit suitable for use in acomputing environment. A computer program can be deployed to be executedon one computer or on multiple computers at one site or distributedacross multiple sites and interconnected by a communication network.

Method steps of the techniques can be performed by one or moreprogrammable processors executing a computer program to performfunctions of the techniques by operating on input data and generatingoutput. Method steps can also be performed by, and apparatus of thetechniques can be implemented as, special purpose logic circuitry, e.g.,an FPGA (field programmable gate array) or an ASIC (application-specificintegrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. The essential elements of a computer area processor for executing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, such as,magnetic, magneto-optical disks, or optical disks. Information carrierssuitable for embodying computer program instructions and data includeall forms of non-volatile memory, including by way of examplesemiconductor memory devices, such as, EPROM, EEPROM, and flash memorydevices; magnetic disks, such as, internal hard disks or removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated inspecial purpose logic circuitry.

A number of implementations of the techniques have been described.Nevertheless, it will be understood that various modifications may bemade. For example, useful results still could be achieved if steps ofthe disclosed techniques were performed in a different order and/or ifcomponents in the disclosed systems were combined in a different mannerand/or replaced or supplemented by other components. Accordingly, otherimplementations are within the scope of the following claims.

1. A computer-readable storage medium storing instruction that, whenexecuted, cause a processor to perform the following operations:receive, during a scanning period in which a portion of a region isimaged by an electron-beam scanner, first data produced by theelectron-beam scanner, the first data including a first indication of acharacteristic of the portion; determine, during the scanning period, acharacteristic of the portion from the first data; provide, during thescanning period, a first input derived from the characteristic to asource of a treatment beam, the first input being sufficient to causethe source of the treatment beam to modify a property of the treatmentbeam; receive, during the scanning period, second data produced by theelectron-beam scanner, the second data being received after the firstdata and the second data including a second indication of thecharacteristic of the portion; determine, during the scanning period,the characteristic of the portion from the second data; and provide,during the scanning period, a second input derived from thecharacteristic determined from the second data to the source of anirradiation beam, the second input being sufficient to cause the sourceof the treatment beam to modify the property of the treatment beam toaccount for the characteristic determined from the second data.
 2. Themedium of claim 1, wherein the property of the treatment beam comprisesa beam profile of the treatment beam.
 3. The medium of claim 1, whereinthe characteristic of the portion comprises a shape of the portion, andthe shape of the portion varies during the scanning period.
 4. Themedium of claim 1, wherein the portion moves during the scanning period.5. The medium of claim 1, wherein the region comprises a human patientand the portion of the region comprises a biological structure withinthe human patient.
 6. The medium of claim 1, wherein the property of thetreatment beam is a beam profile of the treatment beam and the firstinput and the second input are inputs sufficient to cause a leaf of amulti-leaf collimator coupled to the source of the treatment beam tomove such that the beam profile is modified.
 7. The medium of claim 1,wherein the characteristic of the portion of the region is a position,and the first input and the second input are inputs sufficient to causethe source of the treatment beam to direct the treatment beam toward theposition of the portion.
 8. The medium of claim 1, wherein the portionof the region comprises a biological structure of a patient, and thescanning period is a continuous treatment session during which thepatient remains in the region and the treatment beam irradiates thebiological structure.
 9. The medium of claim 1, wherein the second inputis provided to the source of the irradiation beam no more than tenhundred milliseconds after the first input is provided to the source ofthe irradiation beam.
 10. A method of controlling a treatment beamduring a scanning period, the method comprising: exposing a portion of aregion to an imaging x-ray beam during a scanning period, the imagingx-ray beam being generated by an electron-beam scanner; detecting x-rayradiation from the region, the x-ray radiation representing anattenuation of the imaging x-ray beam caused by the portion of theregion; generating a first image of the portion of the region based onthe detected x-ray radiation; determining a characteristic of theportion of the region from the generated first image; generating aninput derived from the characteristic, the input configured to cause asource of a treatment beam to modify a property of the treatment beam;and causing the source of the treatment beam to modify a property of thetreatment beam during the scanning period by providing the input to thesource of the treatment beam.
 11. The method of claim 10, wherein thecharacteristic of the portion comprises the position of the portion, andcausing the source of the treatment beam to modify a property of thetreatment beam comprises modifying a direction of propagation of thetreatment beam such that the treatment beam irradiates the portion.